Excavating tooth having outwardly slanted ribs

ABSTRACT

A replaceable tooth for excavating equipment, such as earth augers, has a distal portion which is generally rectangular in plan but has an inwardly curved cutting edge. The distal is formed with ribs on the upper surface which originate at a transverse protuberance at the rear of the distal and slant forwardly-outwardly to the front corners of the tooth. On the bottom surface, a corresponding protuberance and ribs of lesser dimension than those on the upper surface underly the upper surface ribs. Between the ribs and outside the ribs the tooth is relatively thin and comprises webs. In use, the webs wear faster than the ribs and expose the ends of the rib in points which improve digging action.

United States Patent 1191 Sturgeon 1 1 June 5, 1973 s41 EXCAVATING TOOTH HAVING 3,136,077 6/1964 OUTWARDLY SLANTED RIBS 3,300,883 967 3,312,002 4/1967 [75] Inventor: Walter L. Sturgeon, Sunnyvale, 3,440,745 4/1969 Calif. I 3,544,166 12/1970 Proctor ..37/l42 R X [73] Asslgnee: g g corporanon Sunnyvale Primary Examiner-Edgar S. Burr a l Attorney-Julian Caplan [22 Filed: Feb. 10, 1972 [21] Appl. No.: 225,118 [57] ABSTRACT A replaceable tooth for excavating equipment, such as Related Appllcatmn Data earth angers, has a distal portion which is generally [63] continuatiomimpan of Ser. 40326 May 25, rectangular in plan but has an inwardly curved cutting 1970, abandone edge. The distal is formed with ribs on the upper surface which originate at a transverse protuberance at 52 us. c1. ..37/142 R, 172/713 the Year Of the distal and slant forwardly-wtwardly to 51 1111.01. .Q .1502! 9/28 the tom-0111118 surface [58] Field 6: Search ..37/142 141- a cmespmding Pmmlmmmce and ribs lesser 5 dimension than those on the upper surface underly the upper surface ribs. Between the ribs and outside the ribs the tooth is relatively thin and comprises webs. In [56] Reta-megs Cited use, the webs wear faster than the ribs and expose the UNITED STATES PATENTS ends of the rib in points which improve digging action.

3,113,390 12/1963 Pewthers .137/142 R 4 Claims, 7 Drawing Figures PATENTEDJUN 5197s I 67 5628 i 28 4/ Fly 36% Fig. 5

as caliche a formation occurring in the western states. It has been found that in order to effectively dig in such soil, an explosive cutting action is required as distinguished from a slicing action; Accordingly, U.S. Pat. No. 3,136,077 shows a central rib which has been found effective in such soil. However, the width of cut of a tooth, according to U.S. Pat. No. 3,136,077, is limited by reason of the shape of the tooth. In accordance with the present invention, a pair of ribs are used which slant upwardly-rearwardly and wedge into hard formations to cause an explosive action rather than the slicing action. 7

Another feature of the invention is the fact that by reason of the fact that the ribs slant outwardly and forwardly from the center when the tooth is viewed in plan, the total width of the tooth tends to be preserved despite extreme wear.

A further feature of the invention is the fact that abrasion improves the cutting action and sharpens the edge of the rib into two points which dig into the formation.

Another feature of the invention is the fact that there are thin webs between the points and these thin webs the forward ends of the ribs and these have the function of fracturing the formation when the tooth is turned relative to the direction of its. movement. It will be understood that in an auger, the outside teeth slant inward and are moving at an angle relative to the formation being cut. The side webs, hereinafter explained in detail, are effective in such angular cutting particularly when the tooth is on the outside of an auger.

The present invention constitutes an improvement over teeth which have previously been successful commercially. Reference is made to U.S. Pat. No. 2,578,014, FIG. 6. This figure shows six teeth on an auger, the outermost teeth being designated by reference numeral 9. In digging in hard soil, it has been found that a tooth, such as U.S. Pat. No. 2,877,574, is necessary because such a tooth has a wide cutting edge which provides the clearance necessary to excavate the full width of the auger head. n the other hand, in very hard and compacted soil, the teeth at positions 9a and 9b in FIG. 6 of said U.S. Pat. No. 2,578,014 may be formed in accordance with U.S. Pat. No. 3,136,077.

Applying teeth in such manner in an auger requires that two separate sets of teeth be stocked.

:'referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is a top plan view of a tooth in with the present invention.

FIG. 2 is a'sectional view taken substantially along the line 22 of FIG. 1.

FIG. 3 is a side elevational view.

accordance FIGS. 4 and 5 are respectfully fragmentary sectional views taken substantially along the lines 4-4 and 5-5 of FIG. 1.

FIG. 6 is a top plan view showing the wear which has occurred in a tooth when positioned midway of the radius of an auger.

FIG. 7 is a view similar to FIG. 6 showing the wear pattern when the tooth has been installed on the out side of an auger.

The tooth of the present invention has a proximal portion 11 which is more or less conventional and is subject to considerable variation and a distal portion 12. A preferred distal shape is illustrated and described, but is subject to variation. In the preferred shape, viewed in plan, the distal portion 12 has straight side edges 13 and at the front has an inwardly curved edge 14. At the back of distal portion 12 is a transverse protuberance 16. The protuberance 16 preferably has a flat crown 17 on the upper surface. Rearwardly of crown 17 and buttressing the same is a curved rear flank 18 on the top surface of the tooth. To the sides of the crown 17 are downwardly-outwardly-rearwardly slanted portions 19 on the top surface. As best shown in FIG. 2, the underside of the protuberance 16 is a relatively flat surface 21. The function of the protuberance 16 is to participate in breaking up the formation and to protect the tooth holder which lies immediately rearwardly thereof from abrasion.

Extending outwardly-forwardly from the middle of protuberance 16 and extending to the forward-outer corners of the tooth are ribs 26 which are disposed at angles of about 20 relative to side edges 13. In a preferred shape, each rib is triangular in cross-section and has a top edge 27 which slants upwardly-rearwardly (see FIG. 2) andmerges with crown 17. The sides 28 of ribs 26 are at about 60 angles and diverge slightly rearwardly so that the ribs 26 are wider toward the rear than they are at the front of the tooth. Corners 29 at the front outside edges of the ribs are beveled at about 45 angles. The bottom rib surfaces 31 are approximately flat and are also wider at the front than at the rear (compare the bottoms 31 at FIG. 4 with FIG. 5). The forward corners 29 are also beveled at about a 45 angle. The rib cross-section may be semi-circular or other shapes.

At the front of the tooth is a front web 36 which fills the space between the ribs 26 and preferably has approximately parallel flat top and bottom surfaces 37, 38. The thickness of front edge 14 of said web 36 is considerably less than the minimum thicknessof the ribs 26.

On either side of the distal I2 is a side web 41 which is also thin and extends outwardly of ribs 26 andforwardly of transverse protuberance l6 and especially forwardly of the slanted portions 19. Web 41 preferably has parallel flat top and bottom surfaces42, 43 which are a slightly less distance apart than the surfaces 37, 38 (compare FIG. 3 with FIG. 2).

The proximal 11 of the tooth is formed with a slot 46 extending forwardly from the rear of the tooth which divides the proximal into two prongs 47 which are substantially rectangular in cross-section. The outside edges 48 of the prongs 47 are in practical effect continuations of the side edges 13. The inside edges 49 are spaced apart and may function in a tooth holder such as is shown in US. Pat. No. 2,952,085 or 2,968,880. The forward end 51 limits inward movement of the tooth 11 relative to its holder, and the top and bottom surfaces 52, 53 are preferably flat and parallel. Ends 54 of prongs 47 are shown rounded in FIG. 1 primarily for manufacturing purposes. It will be understood that the proximal end of the tooth may be varied depending on the holder with which it is to be used.

One of the features of the invention is the explosive action on hard formation occasioned by the ribs 26 fragmenting the soil and breaking it into small pieces rather than slices or powder. This effect is obtained wherever the tooth is located in excavating equipment; for example, either on the inside or outside of an auger or an intermediate position.

Directing attention to FIG. 6 of the accompanying drawings, the solid lines indicate the contour of the tooth after considerable wear in a position such as the teeth marked 9a or 9b in FIG. 6 of U.S. Pat. No.

2,578,014. It will be seen that the forward edge 14 of the web has worn back so that the edge 56 is of a smaller radius than the initial edge 14. The outside side edges 57 and 58 are substantially identical and should be identical in theory. Points 59a and 59b are formed as the tooth wears at the intersections of edge 56 with edges 57 and 58 respectively. The points 59a, 59b effectively dig into the soil as fingers, and the ridges of the ribs 26 constitute in effect continuations of the points 58, 59.

Directing attention to FIG. 7 of the accompanying drawings, this figure shows in plan the wear which has occurred in a tooth which was located in the position 9 of FIG. 6 of US. Pat. No. 2,578,014 and the left-hand side of FIG. 7 was outermost. It will be seen that the forward edge 61 has worn back almost to the protuberance 16. The side edge 62 has worn back to a greater extent than the side edge 63 because the wear is great- .est on the outside edge. Outside and inside points 64,

66 have been left at the exposed outer ends of the ribs v 26, the point 66 being farther from the proximal of the tooth than the point 64, again because of the fact that the outside of the tooth wears more rapidly than the inside. Although the tooth of FIG. 7 is practically totally worn out, it is observed that the points 64, 66 are still in place and are available for further digging action if such were required.

What is claimedis:

rear end forwardly and outwardly toward each front corner of said tooth in a pair of outwardly-forwardly extending first ribs, the elevations of said ribs diminishing forwardly and being triangular in cross-section, the bottom of said distal portion underlying said protuber ance being coplanar with the bottom of said proximal portion, and having outwardly-forwardly extending second ribs having flat outer surfaces underlying said first ribs, the portion of said distal portion between said ribs and forward of said protuberance substantially filling the space between said ribs and comprising a thin front web having a shallow concave front edge, the bottom of said front web being parallel to but elevated above said bottom surfaceof said proximal portion and the top of said front web being parallel to and at an elevation below said top surface of said proximal portion, the portions outward on either side of said ribs and forward of said protuberance comprising thin side webs extending to said side edges of said distal portion, said side webs having parallel top and bottom surfaces spaced apart a lesser distance than but parallel to said top and bottom surfaces of said front web, whereby said ribs dig into compacted soil with an explosive action and cut the full width of said tooth whether said tooth is moving forwardly or at an angle to the forward edge of said tooth.

2. A tooth according to claim 1 in which said top protuberance is higher than said proximal portion and higher than any other portion of said distal portion.

3. A tooth according to claim 2 in which said top protuberance is flat at the middle and slopes downwardly on either side and also rearward and merges in elevation with the forward end of said-proximal portion.

4. A tooth according to claim 1 in which said proximal portion has parallel top and bottom surfaces and is formed into two longitudinal prongs of rectangular cross-section by a slot extending forward from the rear of said tooth to adjacent the forward end of said proximal portion, the top surfaces of said webs being lower than the top surface of said proximal portion and the bottom surfaces of said webs being higher than the bottom surface of said proximal portion. 

1. An excavating tooth comprising a proximal portion shaped for being detachably held in a tooth holder and having substantially parallel side edges and flat, parallel top and bottom surfaces, and a distal portion having substantially parallel side edges extending forwardly as continuations of said side edges of said proximal portion, the top of said distal portion having a protuberance at the center rear end of said distal portion which extends transversely and rearwardly toward each side edge of the tooth and also extends from said center rear end forwardly and outwardly toward each front corner of said tooth in a pair of outwardly-forwardly extending first ribs, the elevations of said ribs diminishing forwardly and being triangular in cross-section, the bottom of said distal portion underlying said protuberance being coplanar with the bottom of said proximal portion, and having outwardly-forwardly extending second ribs having flat outer surfaces underlying said first ribs, the portion of said distal portion between said ribs and forward of Said protuberance substantially filling the space between said ribs and comprising a thin front web having a shallow concave front edge, the bottom of said front web being parallel to but elevated above said bottom surface of said proximal portion and the top of said front web being parallel to and at an elevation below said top surface of said proximal portion, the portions outward on either side of said ribs and forward of said protuberance comprising thin side webs extending to said side edges of said distal portion, said side webs having parallel top and bottom surfaces spaced apart a lesser distance than but parallel to said top and bottom surfaces of said front web, whereby said ribs dig into compacted soil with an explosive action and cut the full width of said tooth whether said tooth is moving forwardly or at an angle to the forward edge of said tooth.
 2. A tooth according to claim 1 in which said top protuberance is higher than said proximal portion and higher than any other portion of said distal portion.
 3. A tooth according to claim 2 in which said top protuberance is flat at the middle and slopes downwardly on either side and also rearward and merges in elevation with the forward end of said proximal portion.
 4. A tooth according to claim 1 in which said proximal portion has parallel top and bottom surfaces and is formed into two longitudinal prongs of rectangular cross-section by a slot extending forward from the rear of said tooth to adjacent the forward end of said proximal portion, the top surfaces of said webs being lower than the top surface of said proximal portion and the bottom surfaces of said webs being higher than the bottom surface of said proximal portion. 